Novel recoverable porous magnetic carbons derived from biobased polybenzoxazine by self-foaming and activation treatment

Abstract

The novel fully biobased polybenzoxazine derived carbon adsorbents containing Fe3O4 magnetic nanoparticles are prepared by solvothermal method, followed by activation and carbonization treatments. There are the polymerization and self-foaming reactions of benzoxazine monomers, and thermal decomposition of Ferrous acetylacetonate during in situ preparation of magnetic carbon precursors. The designed and fabricated pentanoic acid type benzoxazine resin not only provides the rich oxygen-containing functional groups but also favors the development of porous structure for the resulting carbon materials. Both self-foaming reaction and activation treatment also benefit the formation of porous structure and improve the specific surface area. The dye adsorption performance, magnetic separability and recyclability of the fabricated carbon materials are investigated through selecting methylene blue as a cationic dye. The magnetic carbon materials occupy good adsorption capacity of cationic dye, resulting from rich oxygen-containing groups, relatively high specific surface area, and well-developed porous microstructure. The adsorption behavior of porous carbon adsorbents is fast, pH-sensitive, Langmuir monolayer adsorption mechanism, and better fitted to pseudo-second-order kinetic model. Moreover, easy magnetic separation and fast regeneration make the magnetic adsorbents suitable to be practically applied in wastewater treatment. Therefore, the flexible and effective strategy in this work may be generally applicable for the structural design and preparation of polymer derived magnetic carbon materials.